Safety shut-off and fire alarm device



May 31, 1955 A. E wcKERs SAFETY SHUT-OFF AND FIRE ALARM DEVICE Filed Sept. 10 1951 INVENTOR. AL RED E. VIQKEQs ATTOEWE'V United States Patent SAFETY SHUT-OFF AND FIRE ALARM DEVICE Alfred E. Vickers, Petersham, Mass. Application September 10, 1951, Serial No. 245,820 4 Claims. (Cl. 200-142) This invention relates to new and improved shut-off devices for electrical and other appliances, in combination with alarm devices operated simultaneously thereby, the principal objects of the invention residing in the provision of a device of the class described providing two relatively fixed and spaced or insulated contacts, one of which is adapted to normally close a circuit to and energize an appliance such as for instance an oil burner, and the other of which is adapted to energize an alarm system adapted to be normally open as to the circuit and closed only upon actuation of the safety device which thereby disconnects and shuts off the appliance such as the oil burner motor and engages and turns on an alarm system, whereby the same may be located adjacent an oil burner or other appliance and not only serve to turn off the oil burner flame as well as the flow of oil, but also to initiate an alarm of any desired kind so as to make known the existence of fire or other undesired high heat conditions.

Another object of the invention resides in the provision of the devices above described used in pluralities of locations as alarm devices only and in combination with one device serving both as an arm or turn-off or circuit interrupters from appliance such as a motor so that all sections of the building or floor may be completely served by the alarm system.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings, in which Fig. l is a view in elevation of the device according to the present invention;

Fig. 2 is a vertical section therethrough;

Fig. 3 is a similar section, taken at right angles to the section of Fig. 2;

Fig. 4 is a simple wiring diagram; and

Fig. 5 is a top plan view of the plug fixture.

As shown in Fig. 1, the device comprises a plate or the like indicated at which may be similar to junction box covers and having a portion thereof indicated at 12 carrying three separate binding posts indicated at 14, 16 and 18. Of course the part 12 may be insulated and the part 10 may take the place of the usual outlet box cover.

Secured to member 10 there is a box 20 depending from which is a cylindrical hollow member or housing 22 having an in-turned circular flange 24 for a purpose to be described.

The post 18 has secured thereto within the housing 20 a leaf type contact arm 26 secured by any desired means to a yoke 28 pivoted as at 30 to a fiber or similar arm 32, the latter being provided with a cross-pin 34 for securement to the head 36 of a screw-type fastening 38.

A spring 40 surrounds the head 36 and reacts against flange 24 and a widened portion of the head 42, see Fig. 2, to provide that the fiber arm 32 be pushed upwardly by spring 40 so as to raise the contact 44 of contact arm 26.

The post 14 is provided with a contact arm 48 and the post 16 is provided with a contact arm 50. In the 2,709,733 Patented May 31, 1955 illustration herein, the contact 48 is normally engaged by contact 44 but when the fiber arm 32 is raised, it breaks this contact and makes contact 50 leading from binding post 16. r

The element 38 in this case is provided with a threaded end at 62 threaded in a fusible plug 54 held in a fixture 56. The fusible plug may be open in the center and threaded, and when the fixture 56 is threaded on to the element 52, it moves the latter downwardly against the action of the spring 40, thus holding the contacts 44 and 48 in the Fig. 3 position to energize the motor indicated at M in Fig. 4. It is to be understood that this motor may be any kind of an electrical appliance, relay, etc.

Contact 50 is connected to the alarm A and it is clear that when the fusible plug 54 is missing or fuses, the element 38 will rise according to spring 40, breaking contact 48 and making contact 50 thus cutting out motor M and energizing the alarm A. All that need be done to reset the alarm device is to replace fixture 56 with a new fixture containing a fusible plug. The fixture containing the fusible plug has of course dropped off and is discarded once having been used.

It is clear that fusible plug devices as above described are easily and inexpensively manufactured and they may be inserted in an electric system to cover all areas of a building or floor, properly connected and spaced according to conditions encountered. In this case, the contact 48 or binding post 14 need not be connected to any appliance and may be omitted, and in such an installation, the entire building or floor is adequately provided With fire alarm signalling means while at the same time the appliances, which may form a source of danger during a fire, may be completely out out by a single device of the nature described.

Having thus described my invention and the advantages thereof, 1 do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. A safety switch and fire alarm device comprising a housing, a pair of fixed contacts in spaced relation there in, a movable contact arm therebetween, means to move the arm to normally close one set of contacts and open the other set, said means including a fusible plug connected to the contact arm and maintaining it in the first position, and means for moving said contact arm in the absence of fusing of said fusible plug to open the one set of contacts and close the other set, a fixture for containing said fusible plug adapted to bear on the said housing, said fixture and plug comprising means interengaging means with the movable contact arm to move the latter to closed condition of the said one set of contacts upon movement of the fixture.

2. A safety switch and fire alarm device comprising a housing, a pair of fixed contacts in spaced relation therein, a movable contact arm therebetween, means to move the arm to normally close one set of contacts and open the other set, said means including a fusible plug connected to the contact arm and maintaining it in the first position, and means for moving said contact arm in the absence of or fusing of said fusible plug to open the one one set of contacts and close the other set, a fixture for said fusible plug adapted to bear on the said housing, said plug forming means interengaging with the movable contact arm to move the latter to closed condition of the said one set of contacts upon motion of the fixture, said fixture being otherwise free of the device and completely separable therefrom upon fusing of the plug.

3. A safety switch and fire alarm device comprising a housing, a fixed contact therein, a movable contact arm, a threaded stem to move the arm to normally close the contact or open the same, a fusible plug threadedly connected to the stem and maintaining the contact arm in the first position, said stern being longitudinally movable in the absence of fusing of said fusible plug by rotating the plug with respect thereto to open the one set of contacts and close the other set, and means holding the fusible plug in rotatable but axially fixed position relative to the housing.

4. A safety switch and fire alarm device comprising a housing, a fixed contact therein, a movable contact arm, a threaded stem to move the arm to normally close the contact or open the same, a fusible plug threadedly connected to the stern and maintaining the contact arm in the first position, said stern being longitudinally movable in the absence of fusing of said fusible plug by rotating the plug with respect thereto to open the one set of contacts and close the other set, and means holding the 1 fusible plug in rotatable but axially fixed position relative 4 to the housing, said means comprising a separate fixture, the plug being fixed therein, and said fixture bearing on the housing and held thereto by the interengagement of the plug and the stem.

References Cited in the file of this patent UNITED STATES PATENTS 487,519 Elliott Dec. 6, 1892 627,837 Wilke June 27, 1899 774,385 Griflin Nov. 8, 1904 2,029,097 Gardner Jan. 28, 1936 2,089,081 Wernple Aug. 3, 1937 FOREIGN PATENTS 327,945 Germany Oct. 19, 1920 

